JP2005169265A - High luminance coated can - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high luminance coated can which has a small change in the color tone of an underlayer and large luminance. <P>SOLUTION: The high luminance coated can is characterized by forming the underlayer 3 printed with an underlying ink on the surface to be coated 2 of the can 1 and an overlayed layer 4 coated with an outer face paint containing a light reflective pigment 10 so that the underlayer 3 is covered. The content of the light reflective pigment in the outer face paint may be 1-30 mass% and the average coating volume of the outer face paint may be 1g/m<SP>2</SP>-30g/m<SP>2</SP>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, a base layer formed by printing a base ink on a surface to be coated and an upper layer formed by coating an outer surface paint containing a light-reflective pigment so as to cover the base layer are formed. Related to the can body.

  In general, a can body such as a beverage can has a base layer formed by printing a base ink on the surface to be coated (the outer surface of the can body), and a transparent outer surface paint is applied on the base layer to form the base layer. After forming, it is manufactured by heating and drying. Here, the upper layer coated with the transparent outer paint has effects such as improving the gloss of the appearance and improving the slipperiness of the can which is advantageous during transportation, while protecting the lower layer.

  In recent years, design properties have been required for the outer surface coating of cans such as the above beverage cans, and there has been a demand for coating cans with a glittering brightness. In response to such a demand, a base layer formed by printing a base ink on the surface to be coated, and an base layer formed by coating an outer surface coating containing a light interference pigment so as to cover the base layer; An optical interference type paint can in which is formed is proposed (for example, see Patent Document 1).

However, in the above-mentioned optical interference type paint can, an optical interference type pigment in which a high refractive index layer made of TiO ₂ or the like is laminated on a low refractive index base material made of Al ₂ O ₃ or SiO ₂ as a pigment for an outer surface coating. Therefore, due to the light interference effect of the light interference pigment, the change in color tone of the base ink of the base layer is large, so that the design of the appearance of the can body may be impaired.
JP 2003-62522 A

  An object of the present invention is to provide a high-brightness paint can having a small change in color tone of a base layer and a high brightness.

The high-brightness coated can according to the present invention includes a base layer on which a base ink is printed on a surface to be coated of the can body, and an outer surface paint containing a light-reflective pigment so as to cover the base layer. An upper layer formed by painting is formed. Here, the content of the light reflective pigments in the outer surface coating 1% by weight to 30% by weight, and may be an average coating weight of the outer surface coating and ^{1g / m 2 ~30g / m 2} . Further, at least 80% by mass of the light reflecting pigment can have an average particle size of 20 μm to 80 μm and a thickness of 3 μm or less. In addition, the light reflection type pigment can have a structure in which a light reflection layer is coated on a scaly substrate. Further, the scaly substrate can be glass flake, and the light reflecting layer can be a metal layer made of gold, silver, aluminum or nickel, or an alloy layer made of these alloys. Further, the lightness L * of the underlayer can be set to L * ≦ 50. Here, the lightness L * refers to the lightness L * in the L * a * b * color system defined by JIS Z 8729.

  According to the present invention, the coated surface of the can body is coated with the ground layer on which the ground ink is printed, and the outer surface paint containing the light-reflective pigment so as to cover the ground layer. By forming the base layer, a high-luminance paint can having a small change in color tone of the base layer and a high luminance can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. One high-intensity coated can according to the present invention, as shown in FIG. 1, is a base layer 3 in which a base ink is printed on the surface 2 to be coated of the can body 1, that is, the outer surface of the can body, and the base layer. 3 is formed, and the upper layer 4 is formed by coating the outer surface paint containing the light-reflective pigment 10. Here, the outer coating material contains the light reflecting pigment 10 in a highly transparent resin. By configuring the high-brightness paint can with the above-mentioned configuration, there is little concealment of designs made up of characters and patterns composed of the base ink of the base layer, there is little color tone change of the base layer, and brightness is improved. Can be made.

  The high brightness paint can is manufactured as follows. Referring to FIG. 1, a base layer 3 is formed by printing a base ink constituting a design composed of characters, patterns, and the like on a surface 2 to be coated of a can body 1. Next, on the base ink of the base layer 3, for example, an outer surface paint containing the light reflecting pigment 10 is applied by a roll coating method, and dried and cured to form the top layer 4. Here, with the roll coating method, the outer surface coating material transferred from the anix roll to the applicator roll was transferred to the outer surface of the base layer 3 by rotating the applicator roll against the base layer 3 while rotating each other. Thereafter, the upper layer 4 is formed by drying. Here, in the roll coating method, the outer surface paint is partially overlapped in order to eliminate the unpainted portion of the outer surface paint. That is, since a portion where the external paint is applied twice occurs on the surface to be coated 2, the amount of the external paint applied has a certain width.

  Here, the resin constituting the base ink for forming the base layer and the resin constituting the outer surface paint for forming the top layer are not particularly limited as long as they are used for manufacturing a normal beverage can. Moreover, the light reflection type pigment contained in the outer surface paint refers to a pigment having a property of reflecting light on its surface. There are no particular restrictions on the material, structure, or shape of the light-reflecting pigment, but as shown in FIG. 2, the light-reflecting pigment 10 is formed by coating a light-reflecting layer 12 on a scaly substrate 11. It is preferable. When coating the outer surface paint by the roll coating method, by using the scale-like light reflecting pigment, the light reflecting pigment 10 is parallel to the surface of the upper layer in the upper layer 4 as shown in FIG. Since it is oriented, the light reflection efficiency is increased and the luminance can be remarkably improved.

In the high-brightness paint can according to the present invention, the content of the light-reflective pigment 10 contained in the outer paint is 1% by mass to 30% by mass, and the average coating amount of the outer paint is 1 g / m ² to It is preferably 30 g / m ² . When the content of the light-reflective pigment is less than 1% by mass, the improvement in luminance is small. If the average coating amount of the outer surface coating is less than 1 g / m ² , the coating strength of the upper layer is reduced, and if it exceeds 30 g / m ² , the amount of the light-reflective pigment contained in the upper layer increases. Geologic design and color hiding are increased. On the other hand, when the average coating amount of the outer surface coating exceeds 30 g / m ² , drying becomes slow, bubbles called blisters are easily generated in the dried coating film, and the upper layer easily breaks due to external impact or the like. From this viewpoint, the average coating amount of the outer surface coating, and more preferably ^{3g / m 2 ~12g / m 2} .

Referring to FIG. 2, in the high-brightness paint can according to the present invention, at least 80% by mass of the light reflective pigment has an average particle diameter L of 20 μm to 80 μm and a thickness D of 3 μm or less. preferable. Here, the thickness of the outer surface coating film (that is, the upper layer) corresponding to a preferable average coating amount of 1 g / m ^{2 to} 30 g / m ² of the outer surface coating is 3 μm to 15 μm. Since the upper layer is formed by applying paint, the upper layer as shown by the broken line in FIG. 1 is used even if a scaly light reflective pigment having an average particle diameter of 20 μm to 80 μm and a thickness of 3 μm is used. No protrusion of the light reflective pigment 10 from 4 is observed. If the average particle size is less than 20 μm, the above-described orientation of the light reflecting pigment is lowered and the light reflection efficiency is lowered, so that the improvement in luminance is reduced. Moreover, when the thickness exceeds 3 μm, irregularities are likely to occur on the surface of the upper layer. If the surface of the upper layer is uneven, the handleability of the can in the iron making process is lowered and the can is easily damaged.

  Further, in the high-brightness paint can according to the present invention, as shown in FIG. 2, the light-reflective pigment 10 is not particularly limited as long as it is formed by coating a light-reflecting layer 12 on a scale-like substrate 11. However, the scale-like substrate 11 is preferably glass flakes. In addition to glass flakes, the scale-like material includes mica, but since glass flakes have a higher flatness on the scale surface than mica, the light reflection layer improves the light reflection efficiency, The brightness can be further improved. The light reflecting layer is preferably a metal layer made of gold, silver, aluminum or nickel or an alloy layer made of an alloy thereof from the viewpoint of mechanical strength and durability.

  Moreover, in the high-intensity coated can according to the present invention, the lightness of the underlayer is not particularly limited, but the lightness L * of the underlayer is preferably L * ≦ 50. Here, the lightness L * refers to the lightness L * in the L * a * b * color system defined by JIS Z 8729. The greater the difference in brightness between the light-reflective pigment and the underlying layer in the upper layer, the easier it is to enhance the brightness feeling of the light-reflective pigment.

  Hereinafter, the present invention will be described based on specific examples. Referring to FIG. 1, a base ink (black ink) in which carbon is added to a polyester resin is printed on an Al metal plate surface of 10 mm × 10 mm and a thickness of 0.23 mm as a painted surface 2 of a can body 1. Thus, the underlayer 3 was formed. On the base ink of this base layer 3, an outer surface paint containing a light-reflective pigment 10 having a content shown in Table 1 in a polyester amino resin that is a mixture of a polyester resin and an amino resin is averaged as shown in Table 1 by roll coating. It apply | coated with the application quantity, it was made to dry-cure at 200 degreeC for 30 second-120 second, the upper layer 4 was formed, and each coating can test piece of Examples 1-21 and Comparative Examples 1-3 was produced. Here, referring to FIG. 2, the light reflective pigment 10 is a pigment obtained by coating glass flakes as a scale-like base material 11 with silver as the light reflective layer 12, and having an average particle size L of 40 μm. The one having a thickness D of 2 μm was used.

  The coated can specimen of the high-intensity coated can according to the present invention obtained as described above has a glitter due to the light reflection of the light-reflective pigment contained in the upper layer in the black of the lower layer of the base ink. The reflected light had a brightness feeling.

  Pencil hardness and cross-cut adhesion were evaluated as the coating film properties of each of the above-mentioned paint can test pieces, and luminance, background visibility and background color tone were evaluated as optical characteristics. The results are summarized in Table 1.

  In Table 1, the average coating amount refers to the average coating amount of the outer surface paint, the content rate refers to the content rate of the light reflecting pigment in the outer surface coating material, and the pencil hardness is defined in JIS K 5600-5-4. The scratch hardness (pencil method) is referred to, and the cross-cut adhesion refers to the adhesion (cross-cut method) defined in JIS K 5600-5-6. In addition, regarding brightness, it was a sensory test by three panelists, and three people recognized that the paint can had a brilliant brightness feeling. Those not present were evaluated as x. Regarding the foundation visible, it was a sensory test by three panelists, and three people acknowledged that they could grasp the design of the foundation layer, one that they accepted, and no one Things were evaluated as x. As for the background color tone, the case where three people recognized that the same chromaticity of the base layer was maintained was evaluated as ◯, the case recognized by one person as Δ, and the case where no one recognized as X.

As shown in Table 1, when the average coating amount is 1.5 g / m ² , 5 g / m ^2, and 15 g / m ² , the content of the light reflecting pigment is 1% by mass to 30% by mass. As a result, the evaluation of Δ or more was obtained for any of luminance, background visible and background color tone. In particular, when the average coating amount is 5 g / m ² , the evaluation is excellent with respect to any of brightness, background visible color, and background color tone within a range of the light reflection pigment content of 1% by mass to 30% by mass. Results were obtained. On the other hand, when the average coating amount was 1.5 g / m ² , the pencil hardness was as low as 1H to 2H, and the painted surface was easily damaged. On the other hand, when the average coating amount is 15 g / m ² , the higher the content of the light reflecting pigment, the more the design and color of the underlayer is concealed by the light reflecting pigment contained in the outer surface paint forming the upper layer. The ratio of the background visible and the background color tone deteriorated.

Next, the lightness L * of the coated can body test pieces of Examples 1, 8, 14, 15 to 21 and Comparative Examples 1 to 3 was measured using a color difference meter (KURABO COLOR-7e manufactured by Kurashiki Boseki Co., Ltd.). Further, as Example 22, a coated can body test piece having an average coating amount of the outer surface coating of 5 g / m ² and a content of the light reflecting pigment in the outer surface coating of 25% by mass was prepared in accordance with the above example. The brightness L * was measured. The results are summarized in Table 2. Here, the lightness L * means the lightness L * in the L * a * b * color system defined by JIS Z 8729.

Here, the lightness L * of only the undercoat layer was not directly measured, but the lightness L * in Comparative Example 1 having the smallest average coating amount of the outer surface coating material containing no light reflecting pigment was 1.5 g / m ^2. This was approximated to the lightness L * of the formation, and this was used as the reference lightness L * of the foundation layer. With respect to the reference lightness L * of the underlayer, the lightness difference ΔL * in Comparative Example 2 in which the average coating amount of the external coating material not containing the light reflecting pigment is 5 g / m ² is 0.18, and the light reflecting pigment is contained. The lightness difference ΔL * in Comparative Example 3 in which the average coating amount of the exterior paint not applied was 15 g / m ² was 0.74.

On the other hand, the lightness difference ΔL * in Example 8 in which the average coating amount of the outer surface coating material containing the light reflecting pigment is 5 g / m ² and the content of the light reflecting pigment is 1% by mass is 1.13. In addition, the lightness difference ΔL * in Example 14 in which the content of the light reflecting pigment was 30% by mass increased to 12.03. Further, the lightness difference ΔL * in Example 15 in which the average coating amount of the outer surface coating material containing the light reflecting pigment is 15 g / m ² and the content of the light reflecting pigment is 1% by mass is 5.92. In addition, the lightness difference ΔL * in Example 21 in which the content of the light-reflective pigment was 30% by mass increased to 46.08. Therefore, the increase in the brightness difference is considered to be mainly due to the increase in luminance derived from the light reflection from the light reflection type pigment.

  As described above, as the content of the light reflecting pigment increases, the brightness difference with respect to the brightness of the underlying layer increases (that is, the brightness increases). Concealment is increased, and the chromaticity of the base layer is lost in the base color tone. From Example 17 and Example 18, the maximum brightness difference in the range where the identity of the chromaticity of the underlayer was not impaired was 18.46.

  Furthermore, it replaced with the light reflection type pigment in the said Examples 1, 8, 14, and 15-22, according to said each Example except having used the light interference type pigment, as Comparative Examples 4-14 in Table 3. A coated can body test piece having an average coating amount (average coating amount of the outer coating material) and a content (content of the light interference type pigment in the outer coating material) shown in the drawing was prepared. L *, brightness difference ΔL * relative to Comparative Example 1 and background color tone were evaluated.

Here, the light interference type pigment is a pigment in which a high refractive index layer is coated on a scaly low refractive index base material, and has a two-layer structure with different refractive indexes, so that two or more interfaces can be formed. A pigment having the characteristic that the color tone changes depending on the viewing angle due to interference of refracted light. In Comparative Examples 4 to 14, the light interference type pigment is a pigment obtained by coating mica, which is a scaly low refractive index base material, with a TiO ₂ layer as a high refractive index layer, and having a particle size of 10 μm to 40 μm. And an optical interference type pigment (Iriodin 217WII manufactured by Merck Japan) having a characteristic of changing the color tone of the underlayer to red. The results of Comparative Examples 1-14 are summarized in Table 3.

  In Comparative Examples 4 to 14 in Table 3, the glittery brightness feeling observed in Examples 1 to 22 in Table 2 was not recognized. In addition, the lightness difference increased with the increase in the content of the light interference pigment, but the degree of increase in the lightness difference was smaller than when the light reflection pigment was contained. That is, when Example 14 and Comparative Example 6 are compared, the average coating amount and the pigment content are the same, but the lightness difference ΔL * of the former containing the light reflecting pigment was 12.03. The latter lightness difference ΔL * containing the light interference pigment remained at 5.13. Further, when Example 21 and Comparative Example 14 were compared, the average coating amount and the pigment content were the same, whereas the former lightness difference ΔL * containing the light reflecting pigment was 46.08. The latter lightness difference ΔL * containing the light interference pigment remained at 22.80. From this, it can be seen that the light reflection type pigment can obtain a brightness difference more than twice that of the light interference type pigment due to its high brightness.

In Table 2, when the average coating amount is 15 g / m ² and the content of the light-reflective pigment is 10% by mass or more, the evaluation of the base color tone is Δ, whereas in Table 3, In this case, when the average coating amount is 15 g / m ² and the content of the light interference pigment is 1% by mass or more, the evaluation of the base color tone is Δ, and the content of the light interference pigment is 10% by mass or more. In this case, the evaluation of the background color tone was x. From this, it can be seen that the light-reflective pigment is superior in maintaining the chromaticity of the underlayer as compared with the light interference pigment.

  In addition, the high-intensity paint can according to the present invention, as shown in Example 17, the evaluation of the background color tone remains ◯ and the brightness difference ΔL * increases to 18.46. As shown in Comparative Example 7, when the brightness difference ΔL * is 2.18, the evaluation of the background color tone is Δ, and as shown in Comparative Example 10, when the brightness difference ΔL * is 10.20, the evaluation of the background color tone is x. It was. That is, the high-intensity paint can according to the present invention has high brightness and excellent chromaticity maintenance of the underlayer compared to the light interference paint can containing the light interference pigment described above. It can be seen that high luminance is exhibited and brightness is increased without impairing the color tone of the underlayer.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  INDUSTRIAL APPLICABILITY The present invention can be widely used in cans such as beverage cans, food cans, and general cans, and a base layer on which a base ink is printed on a surface to be coated of the can, and the base layer is covered. Thus, by forming the upper layer formed by coating the outer surface paint containing the light-reflective pigment, a high-luminance coated can with a small luminance change and a high luminance can be obtained.

It is sectional drawing of the to-be-painted surface of the one high-intensity coating can concerning this invention. It is sectional drawing of the one light reflection type pigment used by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Can body, 2 surface to be coated, 3 ground layer, 4 upper layer, 10 light reflection type pigment, 11 base material, 12 light reflection layer.

Claims (6)

  On the coated surface of the can body, there are formed a base layer on which a base ink is printed, and an upper layer on which an outer surface paint containing a light-reflective pigment is coated so as to cover the base layer. A high-luminance paint can characterized by 1 to 30 wt% light reflective pigment content of the outer surface coating, and high luminance coating cans according to claim 1, wherein the average coating amount of the outer surface coating is 1 to 30 g / m ^2.   The high-intensity paint can according to claim 1 or 2, wherein at least 80% by mass of the light-reflective pigment has an average particle size of 20 to 80 µm or less and a thickness of 3 µm or less.   The high-intensity paint can according to any one of claims 1 to 3, wherein the light-reflecting pigment is formed by coating a light-reflecting layer on a scaly substrate.   The high-brightness paint can according to claim 4, wherein the scaly substrate is glass flake, and the light reflecting layer is a metal layer made of gold, silver, aluminum or nickel, or an alloy layer made of an alloy thereof.   The brightness L * of an underlayer is L * ≦ 50, The high-intensity paint can according to any one of claims 1 to 5.

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